In heavy medium saucepan over moderate heat, combine cranberries, sugar, and 1/2 cup water. Bring to boil, stirring often to dissolve sugar, then reduce heat to moderately low and simmer, stirring often, until thickened and reduced to about 3 cups, about 15 minutes.
Transfer to medium bowl and cool, stirring often, until tepid, about 30 minutes. Stir in vodka and liqueur. Transfer to serving bowl, cover, and refrigerate until chilled and set, at least 2 hours. (Sauce can be made up to 2 weeks ahead and refrigerated.) Serve chilled or at room temperature.
Test-Kitchen Tips: Thanks to its high acidity, which discourages bacteria growth, cranberry sauce keeps very well. It can be made and refrigerated at least two weeks before serving, and leftovers are likely to keep for another two weeks. Buy extra fresh cranberries during their season to freeze and add to baked goods. Do not defrost them before use, but do allow an extra few minutes baking time, as the frozen berries will chill the batter.